Can plant material be considered part of cultural heritage? A lesson from Vitis vinifera L. remains stored in the Museo Archeologico Nazionale di Napoli, (Italy)

Since 1738, archaeological sites in the area around Mount Vesuvius have produced large quantities of botanical remains, constituting the Collezione dei Commestibili e degli Avanzi organici (i.e. Collection of Edibles and Organic Remains), currently housed in the Museo Archeologico Nazionale in Naples. It is considered as one of the most extensive collections from the classical world and provides in-depth evidence of Roman dietary habits. A significant portion of the material, in fact, can be attributed to food-related taxa, including a distinctive historical find consisting of thousands of uncharred remains of Vitis vinifera L. (i.e. grapevine). The carpological assemblage is composed by 6 kilos of grapes, peduncles, stalks and pips attributed to marc remains. A multidisciplinary study (morpho-anatomical and Nuclear Magnetic Resonance analysis, as well as Radiocarbon dating) of these specimens allowed to establish that the collection also includes ‘historically false material’. Indeed, the histological structure of the grape seeds and the lignified cell layers appear well preserved. Radiocarbon dating has shown that the material does not date back to the Roman period, but that the age of the Vitis remains can be placed between 1782 and 1796, the period corresponding to the first excavations carried out in the Vesuvian area. Accordingly, in order to reconstruct the history of this material, a complementary review of published works, archival records and inventories was carried out, which revealed that the first mention of this material in archival sources appeared in 1885 and has been listed incorrectly ever since. The information obtained from the survey of archival material and experimental analysis allowed to emphasize the lack of attention, study and inadequate conservation methods of archaeobotanical material.